This invention relates to a gas filtering device for a light gas tank, particularly to one combined on a tank and a filter combined under a lower end of a gas passageway in a control valve for filtering fuel gas stored in the tank when it is to be used so that water and miscellaneous matters in the fuel gas may be removed and the fuel gas may become pure to burn completely.
Common conventional gas tanks always have a control valve combined with a tank for controlling fuel gas stored therein to flow out for use. The tank is made of steel, and in cold and wet weather, moisture may penetrate into the tank to become water mixed in fuel gas. In addition, fuel filled in the tank may also contain some water and miscellaneous matters more or less. Besides, the steel tank itself may produce corrosion by oxidization, resulting in miscellaneous oxidized matters mixing in fuel stored in a tank. Then fuel gas mixed with water and miscellaneous matters produces a large quantity of carbide in burning, possible to block the nozzle of a gas appliance. In addition, it will burn with red color, with heat gain decreased naturally. So its burning is unstable, either resulting in incomplete burning or a large quantity of carbon monoxide or dioxide, giving rise to danger of a user or dying out of an oven fire.